In liquid chromatography, a fluidic sample and an eluent (liquid mobile phase) may be pumped through conduits and a column in which separation of sample components takes place. In a sample loop, the sample may be injected into a fluidic path by a mechanically drivable needle. The drivable needle is controllable to be moved out of a seat of the sample loop into a vial or any other fluid container to receive a fluid and back from the vial into the seat. The column may comprise a material which is capable of separating different components of the fluidic analyte. Such a material, so-called beads which may comprise silica gel, may be filled into a column tube which may be connected downstream to other components, such as a detector, a fractioner, a waste, etc., by conduits.
An autosampler can be used in liquid chromatography applications, and comprises an injection needle and a corresponding needle seat. In certain known autosamplers, a robot grips the needle and inserts the needle into the needle seat, wherein the robot applies a sealing force to achieve a high pressure resistant sealing between needle and needle seat. When different kinds of needles are used for different applications, the robot has to apply sealing forces of different values to the needle-seat arrangement. For instance, when a ceramic needle for biological applications is used, another sealing force is required as compared to a scenario in which a stainless steel needle is used. This requires to program or adjust the robot in a way that different needle force values can be applied depending on the used needle. Thus, in conventional systems, the injection needle is mounted to a robot arm and is pressed into the sealing seat with a fixed force. The sealing force is defined by a loading spring inside the robot arm. Hence, the sealing force is defined by the robot system. If an injection needle is a used with different material or sealing geometry (for instance bioinert, 600 bar-resistant, 1200 bar-resistant), the sealing force has to be changed via firmware or software of the needle drive. Hence, proper sealing between an injection needle and a needle seat is still a challenge, particularly when a high degree of flexibility is desired to use such a system for different applications.
What is needed is a device that enables efficient fluid handling in a separation system.